The present invention relates to an endless track drive system. Endless track drive systems are used on vehicles such as tractors, bulldozers and tanks.
Many efforts have been made to improve endless track drive systems In Edwards U.S. Pat. No. 4,093,318 issued June 6, 1978 (fully incorporated herein by reference), an endless track drive system is disclosed and claimed which includes a plurality of endless track drive sections, each section having a substantially flat contact surface and sloped surfaces to distribute weight and shed dirt and other foreign objects. Although U.S. Pat. No. 4,093,318 represented a marked improvement in endless track drive systems existing prior to that time the pivotal means of connecting the endless track drive sections was subject to excessive wear, and the endless track drive system there disclosed continued to be excessively costly and time-consuming to make, and it was further found that dirt and foreign objects continued to interfere with proper operation of the endless track drive system, although again not to the extent of track drive systems existing prior thereto.
In further recent developmental work Edwards and his partners/co-inventors Harper and McNew have further improved upon the endless track drive system disclosed in Edwards U.S. Pat. No. 4,093,318. Their U.S. Pat. Nos 4,569,561 issued Feb. 11, 1986, and 4,616,883 issued Oct. 14, 1986 (both full incorporated herein by reference), disclose and claim an endless track drive system made up of a number of drive sections interconnected by cable connector sections. As there disclosed, the drive sections have sloping sides with removable rubber wear pads, and the cable connector sections include cables encased in rubber or other similar suitable material. As a result of such features, the endless track drive system disclosed and claimed therein experiences improved flexibility and tensile strength, reduced noise, and reduced maintenance. The detrimental effects of dirt and debris are likewise mitigated.
Despite the marked improvement in endless track drive systems resulting from the recent work of Edwards, Harper and McNew, as represented in U.S. Pat. Nos. 4,569,561 and 4,616,883, there remains a need for simplification in the manufacture and use of even that improved endless track drive system. Furthermore, the industry is always interested in and receptive to mitigating even further the effects of dirt and debris on endless track drive systems because of the resulting operational problems, downtime and increased maintenance.
An endless track drive system is also known which utilizes a friction drive elastomeric closed loop endless drive track, such as the one depicted in FIGS. 21 and 22 herein. As there depicted, this endless track drive system 81 comprises an elastomeric closed loop endless drive track 82 with tread members 84 and guide members 83 joined to and extending in a direction internally of the drive track. The drive track 82 has reinforcement elements 85a-85d, and is driven by drive wheels 86 in frictional contact with flat lands 82a of drive track 82. This type of endless track drive system is disclosed in PCT Publication No. WO 85/2824 (July 4, 1985).
Unfortunately, the above-discussed endless track drive system of PCT Publication No. WO 85/2824 suffers from a number of deficiencies. For example, in certain types of terrains vehicles equipped with such an endless track drive system have experienced unacceptable slippage, thereby preventing optimal utilization of such vehicles over such terrains. Secondly, although the friction drive wheels of such endless track drive system were designed to dissipate dirt and debris, entrapment of dirt and debris continues to be a problem due to the horizontal engagement between the drive wheels and the drive track.
Thus, there remains a need for an improved endless track drive system which overcomes the foregoing problems.